Text::CSV provides facilities for the composition and decomposition of comma-separated values using Text::CSV_XS or its pure Perl version.

An instance of the Text::CSV class can combine fields into a CSV string and parse a CSV string into fields.

The module accepts either strings or files as input and can utilize any user-specified characters as delimiters, separators, and escapes so it is perhaps better called ASV (anything separated values) rather than just CSV.

Important Note: The default behavior is to only accept ASCII characters. This means that fields can not contain newlines. If your data contains newlines embedded in fields, or characters above 0x7e (tilde), or binary data, you *must* set binary => 1 in the call to new (). To cover the widest range of parsing options, you will always want to set binary.

But you still have the problem that you have to pass a correct line to the parse () method, which is more complicated from the usual point of usage:

On combining (print () and combine ()), if any of the combining fields was marked UTF8, the resulting string will be marked UTF8.

Note however if the backend module is Text::CSV_XS, that all fields before the first field that was marked UTF8 and contained 8-bit characters that were not upgraded to UTF8, these will be bytes in the resulting string too, causing errors. If you pass data of different encoding, or you don't know if there is different encoding, force it to be upgraded before you pass them on:

An end-of-line string to add to rows. undef is replaced with an empty string. The default is $\. Common values for eol are "\012" (Line Feed) or "\015\012" (Carriage Return, Line Feed). Cannot be longer than 7 (ASCII) characters.

If both $/ and eol equal "\015", parsing lines that end on only a Carriage Return without Line Feed, will be parsed correct. Line endings, whether in $/ or eol, other than undef, "\n", "\r\n", or "\r" are not (yet) supported for parsing.

When this option is set to true, whitespace (TAB's and SPACE's) surrounding the separation character is removed when parsing. If either TAB or SPACE is one of the three major characters sep_char, quote_char, or escape_char it will not be considered whitespace.

So lines like:

1 , "foo" , bar , 3 , zapp

are now correctly parsed, even though it violates the CSV specs.

Note that all whitespace is stripped from start and end of each field. That would make it more a feature than a way to be able to parse bad CSV lines, as

Under normal circumstances, CSV data makes no distinction between quoted- and unquoted empty fields. They both end up in an empty string field once read, so

1,"",," ",2

is read as

("1", "", "", " ", "2")

When writing CSV files with always_quote set, the unquoted empty field is the result of an undefined value. To make it possible to also make this distinction when reading CSV data, the blank_is_undef option will cause unquoted empty fields to be set to undef, causing the above to be parsed as

The char used for quoting fields containing blanks, by default the double quote character ("). A value of undef suppresses quote chars. (For simple cases only). Limited to a single-byte character, usually in the range from 0x20 (space) to 0x7e (tilde).

By default, parsing fields that have quote_char characters inside an unquoted field, like

1,foo "bar" baz,42

would result in a parse error. Though it is still bad practice to allow this format, we cannot help there are some vendors that make their applications spit out lines styled like this.

In case there is really bad CSV data, like

1,"foo "bar" baz",42

or

1,""foo bar baz"",42

there is a way to get that parsed, and leave the quotes inside the quoted field as-is. This can be achieved by setting allow_loose_quotesAND making sure that the escape_char is not equal to quote_char.

The character used for escaping certain characters inside quoted fields. Limited to a single-byte character, usually in the range from 0x20 (space) to 0x7e (tilde).

The escape_char defaults to being the literal double-quote mark (") in other words, the same as the default quote_char. This means that doubling the quote mark in a field escapes it:

"foo","bar","Escape ""quote mark"" with two ""quote marks""","baz"

If you change the default quote_char without changing the default escape_char, the escape_char will still be the quote mark. If instead you want to escape the quote_char by doubling it, you will need to change the escape_char to be the same as what you changed the quote_char to.

If this attribute is TRUE, you may use binary characters in quoted fields, including line feeds, carriage returns and NULL bytes. (The latter must be escaped as "0.) By default this feature is off.

If a string is marked UTF8, binary will be turned on automatically when binary characters other than CR or NL are encountered. Note that a simple string like "\x{00a0}" might still be binary, but not marked UTF8, so setting { binary => 1 } is still a wise option.

A set of column types; this attribute is immediately passed to the types method below. You must not set this attribute otherwise, except for using the types method. For details see the description of the types method below.

By default the generated fields are quoted only, if they need to, for example, if they contain the separator. If you set this attribute to a TRUE value, then all defined fields will be quoted. This is typically easier to handle in external applications.

By default, a space in a field would trigger quotation. As no rule exists this to be forced in CSV, nor any for the opposite, the default is true for safety. You can exclude the space from this trigger by setting this option to 0.

By default, a NULL byte in a field would be escaped. This attribute enables you to treat the NULL byte as a simple binary character in binary mode (the { binary => 1 } is set). The default is true. You can prevent NULL escapes by setting this attribute to 0.

By default, the parsing of input lines is as simple and fast as possible. However, some parsing information - like quotation of the original field - is lost in that process. Set this flag to true to be able to retrieve that information after parsing with the methods meta_info (), is_quoted (), and is_binary () described below. Default is false.

This is a quite controversial attribute to set, but it makes hard things possible.

The basic thought behind this is to tell the parser that the normally special characters newline (NL) and Carriage Return (CR) will not be special when this flag is set, and be dealt with as being ordinary binary characters. This will ease working with data with embedded newlines.

When verbatim is used with getline (), getline () auto-chomp's every line.

Imagine a file format like

M^^Hans^Janssen^Klas 2\n2A^Ja^11-06-2007#\r\n

where, the line ending is a very specific "#\r\n", and the sep_char is a ^ (caret). None of the fields is quoted, but embedded binary data is likely to be present. With the specific line ending, that should not be too hard to detect.

By default, Text::CSV' parse function however is instructed to only know about "\n" and "\r" to be legal line endings, and so has to deal with the embedded newline as a real end-of-line, so it can scan the next line if binary is true, and the newline is inside a quoted field. With this attribute however, we can tell parse () to parse the line as if \n is just nothing more than a binary character.

For parse () this means that the parser has no idea about line ending anymore, and getline () chomps line endings on reading.

Similar to combine () + string () + print, but more efficient. It expects an array ref as input (not an array!) and the resulting string is not really created (XS version), but immediately written to the $io object, typically an IO handle or any other object that offers a print method. Note, this implies that the following is wrong in perl 5.005_xx and older:

open FILE, ">", "whatever";
$status = $csv->print (\*FILE, $colref);

as in perl 5.005 and older, the glob \*FILE is not an object, thus it does not have a print method. The solution is to use an IO::File object or to hide the glob behind an IO::Wrap object. See IO::File and IO::Wrap for details.

For performance reasons the print method doesn't create a result string. (If its backend is PP version, result strings are created internally.) In particular the $csv->string (), $csv->status (), $csv-fields ()> and $csv->error_input () methods are meaningless after executing this method.

This object function constructs a CSV string from the arguments, returning success or failure. Failure can result from lack of arguments or an argument containing an invalid character. Upon success, string () can be called to retrieve the resultant CSV string. Upon failure, the value returned by string () is undefined and error_input () can be called to retrieve an invalid argument.

This is the counterpart to print, like parse is the counterpart to combine: It reads a row from the IO object $io using $io->getline () and parses this row into an array ref. This array ref is returned by the function or undef for failure.

When fields are bound with bind_columns (), the return value is a reference to an empty list.

This will return a reference to a list of getline ($io) results. In this call, keep_meta_info is disabled. If $offset is negative, as with splice (), only the last abs ($offset) records of $io are taken into consideration.

This object function decomposes a CSV string into fields, returning success or failure. Failure can result from a lack of argument or the given CSV string is improperly formatted. Upon success, fields () can be called to retrieve the decomposed fields . Upon failure, the value returned by fields () is undefined and error_input () can be called to retrieve the invalid argument.

You may use the types () method for setting column types. See the description below.

Takes a list of references to scalars to store the fields fetched getline () in. When you don't pass enough references to store the fetched fields in, getline () will fail. If you pass more than there are fields to return, the remaining references are left untouched.

If parse () or getline () was used with an IO stream, this method will return true (1) if the last call hit end of file, otherwise it will return false (''). This is useful to see the difference between a failure and end of file.

Where $column_idx is the (zero-based) index of the column in the last result of parse ().

This returns a true value if the data in the indicated column was enclosed in quote_char quotes. This might be important for data where ,20070108, is to be treated as a numeric value, and where ,"20070108", is explicitly marked as character string data.

Where $column_idx is the (zero-based) index of the column in the last result of "getline_hr".

while (my $hr = $csv->getline_hr ($fh)) {
$csv->is_missing (0) and next; # This was an empty line
}

When using "getline_hr" for parsing, it is impossible to tell if the fields are undef because they where not filled in the CSV stream or because they were not read at all, as all the fields defined by "column_names" are set in the hash-ref. If you still need to know if all fields in each row are provided, you should enable keep_meta_info so you can check the flags.

If (and only if) an error occurred, this function returns the diagnostics of that error.

If called in void context, it will print the internal error code and the associated error message to STDERR.

If called in list context, it will return the error code and the error message in that order. If the last error was from parsing, the third value returned is the best guess at the location within the line that was being parsed. It's value is 1-based.

Note: $pos returned by the backend Text::CSV_PP does not show the error point in many cases (see to the below line). It is for conscience's sake in using Text::CSV_PP.

If called in scalar context, it will return the diagnostics in a single scalar, a-la $!. It will contain the error code in numeric context, and the diagnostics message in string context.

Depending on the used worker module, returned diagnostics is different.

Text::CSV_XS parses csv strings by dividing one character while Text::CSV_PP by using the regular expressions. That difference makes the different cause of the failure.

When called as a class method or a direct function call, the error diag is that of the last new () call.

If an error occurred, $csv->error_diag () can be used to get more information on the cause of the failure. Note that for speed reasons, the internal value is never cleared on success, so using the value returned by error_diag () in normal cases - when no error occurred - may cause unexpected results.

This module, Text::CSV was firstly written by Alan Citterman which could deal with only ascii characters. Then, Jochen Wiedmann wrote Text::CSV_XS which has the binary mode. This XS version is maintained by H.Merijn Brand and Text::CSV_PP written by Makamaka was pure-Perl version of Text::CSV_XS.

Now, Text::CSV was rewritten by Makamaka and become a wrapper to Text::CSV_XS or Text::CSV_PP. Text::CSV_PP will be bundled in this distribution.

When you use Text::CSV, it calls a backend worker module - Text::CSV_XS or Text::CSV_PP. By default, Text::CSV tries to use Text::CSV_XS which must be complied and installed properly. If this call is fail, Text::CSV uses Text::CSV_PP.

The required Text::CSV_XS version is 0.41 in Text::CSV version 1.03.

If you set an environment variable PERL_TEXT_CSV, The calling action will be changed.

Alan Citterman <alan[at]mfgrtl.com> wrote the original Perl module. Please don't send mail concerning Text::CSV to Alan, as he's not a present maintainer.

Jochen Wiedmann <joe[at]ispsoft.de> rewrote the encoding and decoding in C by implementing a simple finite-state machine and added the variable quote, escape and separator characters, the binary mode and the print and getline methods. See ChangeLog releases 0.10 through 0.23.

H.Merijn Brand <h.m.brand[at]xs4all.nl> cleaned up the code, added the field flags methods, wrote the major part of the test suite, completed the documentation, fixed some RT bugs. See ChangeLog releases 0.25 and on.

Makamaka Hannyaharamitu, <makamaka[at]cpan.org> wrote Text::CSV_PP which is the pure-Perl version of Text::CSV_XS.